Moving surface to reduce drag

ABSTRACT

VEHICLES (E.G., BOATS AND SHIPS) ARE EQUIPPED WITH FREELY MOVABLE SURFACES CONTACTING THE FLUID MEDIUM THROUGH WHICH THE VENICLES TRAVEL. DURING TRAVEL THE SURFACES MOVE IN A DIRECTION OPPOSITE TO THE DIRECTION OF TRAVEL.

Nov. 23, 1971 R. E. FOSTER MOVING SURFACE TO REDUCE DRAG 2 Sheets-Shoot 1 Filed Sept. 15, 1969 l 'Gn l 11 11111111 IIIIIIIIIIIIIIIIJJI 111111111111/1/1/111 IIIIII 11111111 I INVENTOR- RICHARD E. FOSTER ATTORNEY Nov. 23, 1971 R. E. FOSTER 3,621,803

MOVING SURFACE TO REDUCE DRAG Filed Sept. 15, 1969 1 2 Sheets-Sheet 8 I8 2| IO IO ifijiq g 1 U m I8 FIG. 4.

INVENTOR. RICHARD E. FOSTER ATTORNEY United States Patent O 3,621,803 MOVING SURFACE TO REDUCE DRAG Richard E. Foster, 5883 Silverleaf, Baton Rouge, La. 70812 Filed Sept. 15, 1969, Ser. No. 857,856 Int. Cl. B63b 1/36' U.S. Cl. 114-67 3 Claims ABSTRACT OF THE DISCLOSURE Vehicles (e.g., boats and ships) are equipped with freely movable surfaces contacting the fluid medium through which the vehicles travel. During travel the surfaces move in a direction opposite to the direction of travel.

This invention relates to means and methods of reducing drag of vehicles as they travel through a fluid medium. More particularly, this invention relates to ships, boats, and like craft having modified hull surfaces exhibiting less drag during use.

BACKGROUND One of the most common ways of reducing vehicular drag involves utilizing physical shapes to which the air or water offers a relatively low resistance. However, there are practical limitations on the extent to which streamlining may be effectively utilized. Furthermore, even the most capably designed vehicles always encounter friction arising between their exteriormost surfaces and the fluid through which they travel.

In seeking to minimize this slidable friction it has been proposed to employ films of air or of liquids of high lubricity between these relatively moving surfaces. Other ways of solving the problem would be a welcome contribution to the art.

THE INVENTION In accordance with this invention a substantial por tion of the surface of the vehicle in contact with the fluid medium is free to move in a direction opposite to the direction of travel of the vehicle. Thus this movable surface continuously travels rearwardly as the vehicle travels forwardly. In this way, the amount of friction between the exterior surface of the vehicle and its surrounding or adjacent fluid medium is significantly reduced. Further, the improvement achieved by this invention may be utilized in conjunction with other techniques of reducing drag, such as streamlining and surface film lubrication.

In order to still further appreciate the practice and advantages of this invention reference should be had to the ensuing description, appended claims and figures of the drawings in which:

FIG. 1 depicts the outside elevation of a panel for a boat hull;

FIG. 2 is a section of FIG. 1 taken along line, 2, 2;

FIG. 3 is a section of FIG. 1 taken along line 3, 3;

FIG. 4 is a section of FIG. 1 taken along line 4, 4; and

FIG. 5 schematically depicts a boat hull fitted with panels of FIG. 1.

Referring to the figures, endless web stretched over end rollers 12 and supporting rollers 14 is positioned within housing 16 whose external face 18 has a rectangular cutaway 19 so as to expose a substantial portion of the exterior surface of web 10. This positioning is such that web 10 is free to revolve around the rollers 12, 14- such as in the direction of arrow Twhile at the same time being in sufficient slidable contact at 21, 23, 25 and 27 to provide a reasonably watertight seal all around the cutaway.

The over-all panel, indicated generally as 30, is utilized in fabricating the hull by mounting it so that the cutaway face 18 and the exposed surface of web 10 will confront and, at least to a substantial extent, will be in direct contact with the water (note FIGS. 4 and 5). Conduit 20 is attached to a source of air under pressure (e.g., in the range of 15 to 50 p.s.i.g.) so as to assist in maintaining the slidable, reasonably watertight seals at 21, 23, 25 and 27 and to force out of the housing via pipe 22 any water that does seep in. It will of course be apparent that any suitable number of these over-all panels 30 may be used in fabricating or remodeling the hull, e.g., they may be arranged side by side and they may be stacked one above another, although of course the port and starboard sides of the hull should be similarly fitted (note FIG. 5). As FIG. 5 suggests, panels 30 may be bowed or otherwise contoured within reasonable limits so as to match the existing or desired contour of the hull.

It will now be evident that as the hull moves through the water in a direction indicated by arrow M the webs 10 revolve such that the outboard portions travel in the direction of arrow T. It will also be seen that a substantial portion of the surface of the hull in contact with the water is composed of a plurality of flexible endless webs 10 whose exteriormost surfaces are essentially the only portion of the webs forming an interface with the water.

For best results the regions of slidable contact at 21, 23, 25 and 27 should be smooth and suitably lubricated or coated so as to minimize friction. Waxy or unctuous lubricants offer the additional advantage of repelling water. Also, the bearings or journals in which the ends of the rollers rotate should be of the low friction type. Naturally the webs will be fabricated of flexible, tough, water-resistant and water-impervious material such as synthetic rubber or other suitable elastomeric substances. For added strength and durability the web or belt may be reinforced with gauze, mesh, strips, cord, fabric, wires, particles or strands of steel, glass, nylon, rayon or the like. The rollers may be fabricated from any suitable material'such as steel or the like although preferably they are made from lightweight, high strength alloys or plastics.

In essence, this invention involves substituting rolling friction for sliding friction in order to achieve reduction in drag. In particular, as the vehicle is started up the friction as between the exteriormost portion of the webs and the surrounding fluid causes the webs to travel in their endless paths. As the craft achieves its desired operating speed the webs achieve a comparable speed of linear travel in the endless paths around the rollers so that sliding friction over the surface of the hull is considerably minimized. It will also be seen that the surrounding fluid contacts only the outermost portion of the web inasmuch as air (or other suitable gas such as engine exhaust, nitrogen or the like) is maintained within the housing. Accordingly, the interior portions of the webs travel through and in contact with a medium offering much lower drag resistance than the fluid outside the vehicle.

Another feature of the invention is that the rollers are not powered. Instead they are freely rotatable and thus no useful work energy is consumed in effecting rotation. This invention comprehends an over-all lower power consumption for vehicular travel than would be achievable by the same craft absent use of the principles of this invention. This invention should also make possible the achievement of faster rates of vehicular travel for any given type of service.

One can readily see that the panels of this invention may be prefabricated and shipped in preformed condition to the site at which the craft is assembled or renovated. The prefabricated panels can be easily installed and, Where desired or necessary, easily replaced. The dimensions of the panels may of course be varied to suit the needs of the occasion. Ordinarily they will be mounted in surface areas normally experiencing the greatest amount of drag and will be mounted so that they are generally flush with the rest of the hull (note FIG. If desired, additional low-friction sealing strips or flaps may be positioned around rectangular cutaway 19 for added insurance against intake of water. When using such sealing strips or flaps it is possible to position web and rollers 12, 14 such that there are a few millimeters of free space all around the interior of cutaway 19, at 21, 23, 25 and 27 and to direct by means of suitable ducts a flow of air from conduit into this free space. In this way, slidable contact at 21, 23, and 27 is replaced by web 10 traveling on a thin film of air at 21, 23, 25 and 27, the combination of the exterior sealing strips or flaps and flowing air being sufi'icient to prevent excessive leakage into the panel. Shielding may be provided on the exterior of the hull in order to protect the webs and associated parts against damage caused by contact with piers, submerged debris or the like.

Although systems involving the freely rotatable endless webs as described above constitute the best mode contemplated for the practice of this invention, other surface modifications may be found suitable for certain applications. For example, the exterior surface of land and air vehicles may comprise a plurality of partially shrouded rollers or spheres mounted in sockets. In either case movement of the vehicle through the surrounding air will result in rotation of the exposed roller or spherical surfaces in an endless path and in a direction opposite to the direction traveled by the vehicle. Another variant is to employ as the outermost surface of land or airborne vehicles panels of pivoted, freely rotatable thin metal or plastic discs which overlap each other so that greater area of the exposed surface rotates toward the rear of the vehicle than rotates toward the front of the vehicle. Here again the rotation is in an endless path.

Self-evidently, the principles of this invention are susceptible to a variety of applications. For example, the invention may be applied to tankers, freighters, landing craft, submarines, destroyers, catamarans, pleasure craft, speed boats, sail boats, barges, missiles, aircraft carriers, trailers, and the like. However, the preferred embodiments of the invention relate to the use on ships or boats of the flexible revolvable endless web constructions described in connection with the drawings.

I claim:

1. A boat hull panel which comprises a flexible water-impervious endless web, a plurality of vertically disposed rollers rotatably supporting the web, a housing having an external wall with a cutaway therein, means for introducing a flow of gas under pressure into the housing and means for removing fluids from the lower region of the housing, the web being disposed within the housing in slidable contact with the interior of said wall so that an exterior surface of the web covers the interior of the entire cutaway and provides a reasonably watertight seal all around the interior of the cutaway.

2. The apparatus of claim 1 wherein the regions of slidable contact between the web and the interior of said wall are lubricated by means of a water repelling waxy or unctuous lubricant.

3. In a method of reducing drag of a ship traveling through water wherein a traveling endless belt in combination with supporting rollers is secured to a ships hull at or below the water line so that the outer portion of the belt is caused to move in a direction opposite to the direction of travel of the ship, the improvement which comprises (a) encasing the belt in a vertically disposed housing having an external wall with a cutaway therein so that the exterior surface of the belt overlaps and is in close proximity to the interior edges of the wall all around the cutaway;

('b) providing fluid draining means within the housing;

and

(c) maintaining gas under pressure within the housing to maintain a reasonably watertight seal all around the interior of the cutaway and to force out of the housing through said draining means any water that does seep into the housing.

References Cited UNITED STATES PATENTS 280,646 7/1883 McDonald ll467 R 670,995 4/1901 Moore ll467 R 3,195,666 7/1965 Lewis et a] ll467 A 3,195,667 7/1965 Williams ll467 A 5 ANDREW H. FARRELL, Primary Examiner 

